While the top metros are displaying signs of saturation, industry executives said that card transactions in towns with populations of up to 1 million have doubled in the two years since demonetisation.

Before the official announcement by PM Modi, the RBI's Central Board, in its meeting had differed with the government's claim that the note ban would curb black money circulation, citing that most cash was in the form of real estate.

The Reserve Bank of India (RBI), in a circular in April, said all system providers will have to ensure that the entire data relating to payment systems operated by them are stored in a system only in India.